I think that IIFIYM is practical in that it gives you a bit of 'wiggle room' to add in foods that you might be especially found of, even if they go against the old dogma of what's "clean" or what's not. The other variables are going to be a matter of personal preference.
-Multiple meals vs a few? I get hungry very easily, and definitely notice a drop in blood sugar when I've gone too long without food. My decision is easy. (plus I actually believe all that old science about nitrogen balance)
-Nutrient timing? I've personally noticed better training sessions when I target certain nutrients around my workouts. I don't need an armchair/youtube 'expert' telling me it doesn't make a difference, because I have no vested interest any further than my own performance. (and yes, you've got guys like Kalman, Berardi, and many other pretty brainy-folks believing it, so you can forgive me if a 16 year old wanna be bodybuilder preaches otherwise -lol)
-'Clean' foods are usually more filling, as Buckeye Girl pointed out. I remember someone asking me during one of my earlier contest preps why I ate so much oatmeal during the day. Simple answer, it's filling, and its #s are fairly low, allowing you to eat more!
-As far as 'crap' goes, I think some people just overgeneralize. For example, PopTarts are a big thing for a lot of competitors. However, most people view them as garbage in terms of nutritional value. Let's look at the new Peanut Butter PopTart nutrition data: 200 cals, 34 carbs, 3 protein, and 6 fat (2 saturated). Now, while IMO this is a pretty decent carb source, with relatively low protein and fat, you have to further take into account the pure psychological benefit of eating something that's not only tasty, but provides a bit of normalcy, or even 'cheating' to what may possibly be a very ho-hum not fun daily eating regimen.